Telescope sights or riflescopes are used by shooters to enable accurate aiming of firearms such as rifles, pistols, shotguns and the like. These optical sights are typically mounted in a elongated tubular barrel or housing carrying conventional ocular and objective lens systems. An erector-lens system is provided between the ocular and objective systems to provide an erect target image for viewing by the shooter. Windage and elevation adjustments permit the sight to be compensated for targets at varying ranges.
A conventional riflescope includes a reticle, typically of cross hair or post form, which is seen by the shooter in silhouette and superimposed over the target image. The position of the firearm is adjusted until the reticle is positioned on a target-image aiming point. The primary advantage of an optical sight is that the target image and reticle are in the same focal plane, eliminating any need for the shooter to shift eye focus between sight and target as must be done with conventional open sights on a rifle. The optical sight may provide fixed or variable magnification of the target image, but such magnification is not an essential feature and is subsidiary to the primary goal of providing a target image and aiming reticle in a single focal plane.
Conventional reticles are highly satisfactory during conditions of full daylight, but most hunting for game animals is done under restricted lighting conditions before sunrise or just before dark. This is because most game animals are nocturnal feeders, and their search for food is made in darkness or in the relatively short periods just before or after full darkness. A conventional optical sight is difficult to use in these conditions of subdued lighting because the reticle is seen in silhouette against a low-contrast dimly lit image of the target and target background. It is not uncommon for a hunter to lose sight of the reticle entirely while attempting to aim at a game animal standing or moving against a dark background of brush or trees. In such conditions, the firearm cannot be accurately sighted, and the animal will probably escape.
The "fading reticle" problem is solved by illuminating the recticle itself (e.g., electrically heated incandescent reticles have been proposed), or preferably by providing a luminous dot or other mark at the aiming point of the sight. Details of the latter solution are shown in U.S. Pat. No. 3,672,782, the disclosure of which is incorporated herein by reference. Briefly, this patent shows a riflescope with a battery-operated internal lamp which projects a luminous reticle pattern (dot, cross hair, etc.) on the sight field of view and centered on the sight aiming point.
The present invention is directed to an improved illuminated-reticle riflescope having a very compact battery-housing and actuating-switch assembly which enhances the styling of the instrument, and is simple and convenient for the shooter to use. The actuating switch is relatively large for ease of operation when the shooter is wearing heavy gloves, and the switch also serves as a removable closure for the battery housing, enabling rapid and tool-free battery replacement. The removable closure shelters the batteries and switch elements from moisture and dirt, and essentially hermetic sealing of the riflescope interior is not affected by use of the invention.
For convenience, the term "riflescope" is used herein to designate any form of optical sighting device as previously described. That is, the term is used in a generic sense to mean any optical aiming device, whether used on a rifle, pistol, shotgun, archery bow, or the like.